fix(module): don't log fatal error when vuex is disabled (#518)

Author: pimlie

lib/module/index.js

@@ -51,7 +51,7 @@ function validateOptions (options) {
   }
 
   // Enforce vuex store because auth depends on it
-  if (!this.options.store) {
+  if (options.vuex && !this.options.store) {
     logger.fatal('Enable vuex store by creating `store/index.js`.')
   }
 }